Due to the large difference in group sizes (Combination having n = 544 and Developers having n = 89), ANCOVA with type 3 sums of squares is run for checking differences between groups. When grouping is ignored, a paired t-test is used instead.
T-tests show that the Current(Q3.3) and Ideal(Q3.4) questions all have significantly different means when grouping is ignored.
ANCOVA shows that there are 2 activities Developers and Combination researchers differ significantly on.
Developers are more likely to express wanting to spend more time on maintenance than those in the Combination grouping. (Q3.3_6 and Q3.4_6)
On the other hand, those in the combination group are more likely to want to allocate more time to meetings in their ideal scheduling than Developers. (Q3.3_8 and Q3.4_8)
Statistical Tests
Requirements
## Anova Table (Type III tests)
##
## Response: Ideal
## Sum Sq Df F value Pr(>F)
## (Intercept) 332.1 1 6.5562 0.01076 *
## Current 7195.0 1 142.0267 < 2e-16 ***
## Group 13.0 1 0.2562 0.61298
## Current:Group 130.7 1 2.5791 0.10896
## Residuals 23860.7 471
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Paired t-test
##
## data: Pair(Current, Ideal)
## t = -1.1336, df = 474, p-value = 0.2575
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## -1.0588084 0.2840716
## sample estimates:
## mean of the differences
## -0.3873684
Software
## Anova Table (Type III tests)
##
## Response: Ideal
## Sum Sq Df F value Pr(>F)
## (Intercept) 3012 1 25.4705 6.428e-07 ***
## Current 11943 1 100.9871 < 2.2e-16 ***
## Group 0 1 0.0006 0.9807
## Current:Group 7 1 0.0582 0.8094
## Residuals 55700 471
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Paired t-test
##
## data: Pair(Current, Ideal)
## t = -10.088, df = 474, p-value < 2.2e-16
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## -6.009098 -4.049849
## sample estimates:
## mean of the differences
## -5.029474
Coding
## Anova Table (Type III tests)
##
## Response: Ideal
## Sum Sq Df F value Pr(>F)
## (Intercept) 7640 1 25.9775 5.011e-07 ***
## Current 32202 1 109.4863 < 2.2e-16 ***
## Group 1 1 0.0037 0.9516
## Current:Group 159 1 0.5404 0.4626
## Residuals 138528 471
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Paired t-test
##
## data: Pair(Current, Ideal)
## t = -4.7079, df = 474, p-value = 3.292e-06
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## -5.466622 -2.247062
## sample estimates:
## mean of the differences
## -3.856842
Testing
## Anova Table (Type III tests)
##
## Response: Ideal
## Sum Sq Df F value Pr(>F)
## (Intercept) 775 1 9.4979 0.002178 **
## Current 4345 1 53.2314 1.267e-12 ***
## Group 29 1 0.3565 0.550762
## Current:Group 4 1 0.0442 0.833504
## Residuals 38448 471
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Paired t-test
##
## data: Pair(Current, Ideal)
## t = 3.2628, df = 474, p-value = 0.001183
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## 0.5945622 2.3949114
## sample estimates:
## mean of the differences
## 1.494737
Debugging
## Anova Table (Type III tests)
##
## Response: Ideal
## Sum Sq Df F value Pr(>F)
## (Intercept) 382.4 1 10.9410 0.001013 **
## Current 1155.2 1 33.0541 1.613e-08 ***
## Group 4.0 1 0.1151 0.734613
## Current:Group 4.1 1 0.1169 0.732563
## Residuals 16460.6 471
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Paired t-test
##
## data: Pair(Current, Ideal)
## t = 16.386, df = 474, p-value < 2.2e-16
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## 6.090185 7.749815
## sample estimates:
## mean of the differences
## 6.92
Maintenance
## Anova Table (Type III tests)
##
## Response: Ideal
## Sum Sq Df F value Pr(>F)
## (Intercept) 397.1 1 14.2125 0.0001840 ***
## Current 2597.9 1 92.9719 < 2.2e-16 ***
## Group 95.8 1 3.4295 0.0646685 .
## Current:Group 414.6 1 14.8392 0.0001333 ***
## Residuals 13160.9 471
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## Group Current.trend SE df lower.CL upper.CL
## Combination 0.228 0.0361 471 0.157 0.299
## Developers 0.531 0.0699 471 0.394 0.668
##
## Confidence level used: 0.95
##
## Paired t-test
##
## data: Pair(Current, Ideal)
## t = 5.41, df = 474, p-value = 1.002e-07
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## 1.199845 2.568576
## sample estimates:
## mean of the differences
## 1.884211
Documentation
## Anova Table (Type III tests)
##
## Response: Ideal
## Sum Sq Df F value Pr(>F)
## (Intercept) 1701.4 1 34.0199 1.015e-08 ***
## Current 3011.5 1 60.2172 5.320e-14 ***
## Group 72.2 1 1.4430 0.2303
## Current:Group 100.8 1 2.0147 0.1564
## Residuals 23555.1 471
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Paired t-test
##
## data: Pair(Current, Ideal)
## t = -5.6254, df = 474, p-value = 3.168e-08
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## -2.619071 -1.263035
## sample estimates:
## mean of the differences
## -1.941053
Meetings
## Anova Table (Type III tests)
##
## Response: Ideal
## Sum Sq Df F value Pr(>F)
## (Intercept) 238.5 1 3.5564 0.059930 .
## Current 4864.6 1 72.5440 < 2.2e-16 ***
## Group 199.3 1 2.9719 0.085376 .
## Current:Group 709.5 1 10.5806 0.001225 **
## Residuals 31584.1 471
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## Group Current.trend SE df lower.CL upper.CL
## Combination 0.576 0.0307 471 0.516 0.636
## Developers 0.258 0.0929 471 0.075 0.440
##
## Confidence level used: 0.95
##
## Paired t-test
##
## data: Pair(Current, Ideal)
## t = 7.4989, df = 474, p-value = 3.195e-13
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## 2.572772 4.399859
## sample estimates:
## mean of the differences
## 3.486316
Training
## Anova Table (Type III tests)
##
## Response: Ideal
## Sum Sq Df F value Pr(>F)
## (Intercept) 924.4 1 14.2850 0.0001773 ***
## Current 1301.3 1 20.1089 9.2e-06 ***
## Group 184.3 1 2.8479 0.0921556 .
## Current:Group 167.3 1 2.5857 0.1085062
## Residuals 30479.1 471
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Paired t-test
##
## data: Pair(Current, Ideal)
## t = -3.2642, df = 474, p-value = 0.001177
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## -2.1348580 -0.5304052
## sample estimates:
## mean of the differences
## -1.332632
Other
## Anova Table (Type III tests)
##
## Response: Ideal
## Sum Sq Df F value Pr(>F)
## (Intercept) 261 1 1.5343 0.2161
## Current 33261 1 195.2458 <2e-16 ***
## Group 91 1 0.5328 0.4658
## Current:Group 11 1 0.0617 0.8039
## Residuals 80236 471
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Paired t-test
##
## data: Pair(Current, Ideal)
## t = -2.06, df = 474, p-value = 0.03995
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## -2.41870123 -0.05708825
## sample estimates:
## mean of the differences
## -1.237895